Les fractures du zygoma : à propos de 276 cas.

Introduction : les fractures de l’os zygomatique revêtent une multitude de variétés anatomo-cliniques à l’origine de retentissement fonctionnel et morphologique. Le but de ce travail est de déterminer et de préciser les circonstances de survenue, la sémiologie clinique et radiologique, l’attitude thérapeutique et le devenir à moyen terme de ces patients.Patients et méthodes : une étude rétrospective a été menée sur des patients ayant présenté une fracture isolée de l’os zygomatique traités au service de chirurgie maxillo-faciale et chirurgie Plastique de l’hôpital militaire d’instruction mohammed V rabat, entre mars 1999 et avril 2009.Résultats : on a inclu 276 dossiers, l’âge moyen des patients a été de 32 ans avec une nette prédominance masculine (89,5%). Les étiologies ont été dominées par les accidents de la voie publique (64,2%). Le diagnostic a été surtout clinique, confirmé par la radiologie. La réduction ouverte a été effectuée dans 173 cas tandis que 31,9% des cas ont nécessité une réduction fermée. Les séquelles les plus fréquentes ont été représentées par les troubles de la sensibilité (19,2%).Conclusion : l’évaluation pré-opératoire doit inclure une évaluation ophtalmologique complète. Les principes chirurgicaux impliqués dans la gestion des fractures du zygoma sont principalement liées à la réduction. Cette expérience valide certaines indications pour la réduction orthopédique et souligne l’intérêt de la réduction sanglante avec fixation par mini plaques visées. L’indication chirurgicale dépend du type de fracture.Objective : Zygomatic bone fractures have many varieties anatomoclinic at the origin of functional impact. The purpose of this work is to determine and to specify arising circumstances, clinical and radiological epidemiology, therapeutic attitude, and become it of these patients in average term.Patients et méthodes : a retrospective study included patients with zygomatic bone fracture, addmitted at facial surgery department of military Hospital and mohammed V Instruction, rabat; between March 1999 and April 2009.Results: We included 276 files, the average age was 32 years old, with male predominance (89,5%). Causes were dominated by the traffic public accidents (64,2 %). Diagnosis is especially clinic, confirmed by radiology. The open reduction was carried out in 173 cases, while 31,9 % of cases necessitate a closed reduction; the most frequent sequels were sensory troubles (19,2 %).Conclusion : Pre-operative evaluation must include a complete ophtalmological evaluation. Surgical principles in zygoma fractures management are principally linked to the reeducation. This experience validates some indications for orthopedic reeducation, and underlines the interest of bloody reeducation with fixing by aimed mini veneers. Surgical indication depends on fracture typ

Liposarcome dorsal: aspect clinique rare

Décrit la première fois par Virchow en 1860, le liposarcome est une tumeur mésenchymateuse rare. Cette rareté est relative car les liposarcomes représentent quand même 14 à 18 % de l'ensemble des tumeurs malignes des parties molles et ils constituent le plus fréquent des sarcomes des parties molles. Pour la majorité des auteurs, il ne se développerait jamais sur un lipome ou une lipomatose préexistant. Nous rapportons un cas de volumineux liposarcome de la face dorsale du tronc. L'histoire de la maladie, l'aspect clinique inhabituel « de tumeur dans tumeur », l'aspect de la pièce opératoire nous fait évoquer la possibilité de la transformation maligne d'un lipome bénin préexistant

Non-locality and Communication Complexity

Quantum information processing is the emerging field that defines and realizes computing devices that make use of quantum mechanical principles, like the superposition principle, entanglement, and interference. In this review we study the information counterpart of computing. The abstract form of the distributed computing setting is called communication complexity. It studies the amount of information, in terms of bits or in our case qubits, that two spatially separated computing devices need to exchange in order to perform some computational task. Surprisingly, quantum mechanics can be used to obtain dramatic advantages for such tasks. We review the area of quantum communication complexity, and show how it connects the foundational physics questions regarding non-locality with those of communication complexity studied in theoretical computer science. The first examples exhibiting the advantage of the use of qubits in distributed information-processing tasks were based on non-locality tests. However, by now the field has produced strong and interesting quantum protocols and algorithms of its own that demonstrate that entanglement, although it cannot be used to replace communication, can be used to reduce the communication exponentially. In turn, these new advances yield a new outlook on the foundations of physics, and could even yield new proposals for experiments that test the foundations of physics.Comment: Survey paper, 63 pages LaTeX. A reformatted version will appear in Reviews of Modern Physic

Prediction of inter-particle adhesion force from surface energy and surface roughness

Fine powder flow is a topic of great interest to industry, in particular for the pharmaceutical industry; a major concern being their poor flow behavior due to high cohesion. In this study, cohesion reduction, produced via surface modification, at the particle scale as well as bulk scale is addressed. The adhesion force model of Derjaguin-Muller-Toporov (DMT) was utilized to quantify the inter-particle adhesion force of both pure and surface modified fine aluminum powders (∼8 μm in size). Inverse Gas Chromatography was utilized for the determination of surface energy of the samples, and Atomic Force Microscopy was utilized to evaluate surface roughness of the powders. Surface modification of the original aluminum powders was done for the purpose of reduction in cohesiveness and improvement in flowability, employing either silane surface treatment or dry mechanical coating of nano-particles on the surface of original powders. For selected samples, the AFM was utilized for direct evaluation of the particle pull-off force. The results indicated that surface modification reduced the surface energy and altered the surface nano-roughness, resulting in drastic reduction of the inter-particle adhesion force. The particle bond number values were computed based on either the inter-particle adhesion force from the DMT model or the inter-particle pull-off force obtained from direct AFM measurements. Surface modification resulted in two to three fold reductions in the Bond number. In order to examine the influence of the particle scale property such as the Bond number on the bulk-scale flow characterization, Angle of Repose measurements were done and showed good qualitative agreements with the Bond number and acid/base surface characteristics of the powders. The results indicate a promising method that may be used to predict flow behavior of original (cohesive) and surface modified (previously cohesive) powders utilizing very small samples